Pulsed high power rf protection using transient voltage suppression (tvs) diode

ABSTRACT

A system for front end protection of an RF receiver against interfering pulsed high power RF signals includes a dual-diode device comprising a first Transient Voltage Suppressor (TVS) diode; and a second TVS diode; wherein the first TVS diode and the second TVS diode are located between an RF input/output and an RF receiver front end.

FIELD OF THE DISCLOSURE

This disclosure relates to RF receiver protection, more particularly, toprotection from pulsed high power RF signals.

BACKGROUND

Increased sensitivity RF receivers require receiver front end protectionagainst pulsed, high power, signals. Using traditional PIN diodes andother known protection techniques falls short in terms of leakage power,input power capability, and package sizing required to meet operationalconstraints. Traditional solutions and protection techniques show alarge leakage spike/pulse that is enough to damage downstreamcomponents.

Typically, to protect against an ESD event a Transient VoltageSuppressor (TVS) diode is used. The TVS diode is designed to fullydissipate the energy of a transient ESD event. The ESD pulse duration isexpected to be very low, and the design of the TVS diode reflects thatshort duration. It is typically not used to protect against long pulsedurations. It is also typically not used in the RF application becauseit provides a large insertion loss due to its higher intrinsiccapacitance.

Typically, to protect against an RF pulsed signal, a PIN diode is used.The PIN diode has a wide intrinsic region and this layer lowers theoverall device capacitance. The lower capacitance may be good for an RFapplication since it provides little insertion loss at the RF frequencyrange when the device is off and it provides a good short circuit whenthe device is on. However, the addition of the intrinsic layer causes alarger turn on delay, which results in leakage power passing throughbefore the protection kicks in. This leakage power is enough to damagedownstream components. This is true for all PIN diodes. What is neededis a device, system, and method with no leakage, sufficient input powercapability, and package sizing to protect RF receivers from interferinghigh power pulsed RF signals.

SUMMARY

An embodiment provides a device for front end protection for an RFreceiver against transient and pulsed high power RF signals comprising adual-diode device comprising a first Transient Voltage Suppressor (TVS)diode; and a second TVS diode in parallel to the first TVS diode;wherein the first TVS diode and the second TVS diode are located betweenan RF input/output (I/O) and the RF receiver front end; and wherein thetransient and pulsed high power RF signals are suppressed by thedual-diode device; whereby the RF receiver front end is protected fromdamage by the transient and pulsed high power RF signals. Inembodiments, the first TVS diode and the second TVS diode are spacedapart by a TVS diode separation distance. In other embodiments, thefirst TVS diode and the second TVS diode are spaced apart by a TVS diodeseparation distance of λ/4 between an RF input/output and the RFreceiver front end. In subsequent embodiments, each of the first TVSdiode and the second TVS diode has one end coupled to a center conductorand a second end coupled to ground. For additional embodiments thedual-diode device is in line with electrical connections between the RFinput/output and the RF receiver front end. In another embodiment, thesuppression is a reflection of the transient and pulsed high power RFsignals, with no leakage. For a following embodiment each of the firstTVS diode and the second TVS diode has one end coupled to a centerconductor and a second end coupled to a shield of a coaxial cablebetween the RF input/output and the RF receiver front end. In subsequentembodiments the insertion loss of the dual diode device is −0.35 dB at 1GHz. In additional embodiments the insertion loss of the dual diodedevice is −0.25 dB at 1 GHz. In included embodiments the dual diodedevice is located on an Input Output (JO) PCB board. In yet furtherembodiments the return loss of the dual diode device is −18 dB at 1 GHz.In related embodiments the return loss of the dual diode device is −24dB at 1 GHz. For further embodiments, each of the first TVS diode andthe second TVS diode is a Semtech RClamp4041ZA TVS diode. In ensuingembodiments the RF receiver is an Identification Friend or Foe (IFF)receiver.

Another embodiment provides a method for front end protection for an RFreceiver against interfering pulsed high power signals using a TransientVoltage Suppressor (TVS) diode component comprising providing the frontend protection TVS diode component, wherein the TVS diode componentcomprises two TVS diodes; receiving an RF signal at an I/O stage;receiving the RF signal, output from the I/O stage, at the TVS diodecomponent; and diverting the pulsed high power signal by the TVS diodecomponent. For yet further embodiments, the two TVS diodes are separatedby a diode separation distance equal to λ/4. For more embodiments, thediverting is a reflection of the interfering pulsed high power signals.In continued embodiments the TVS diode component is provided in linewith electrical connections between the I/O stage and the RF receiver.For additional embodiments, the TVS diode component limits theinterfering pulsed high power signal by 43 dB at 1 GHz.

A yet further embodiment provides a system for front end protection foran RF receiver against a pulsed high power RF signal comprising adual-diode device comprising a first Transient Voltage Suppressor (TVS)diode; and a second TVS diode electrically parallel to the first TVSdevice; wherein the first TVS diode and the second TVS diode are spacedat λ/4 between each other, and the dual-diode device is electricallyconnected between an RF input/output an Identification Friend or Foe(IFF) RF receiver; and whereby the RF receiver is protected from damageby the pulsed high power RF signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an application environment in accordance with anembodiment.

FIG. 2 illustrates a pulse modulated high-power RF signal waveform inaccordance with an embodiment.

FIG. 3 is a device block diagram in accordance with an embodiment.

FIG. 4 is a device detail in accordance with an embodiment.

FIG. 5 is a flow chart depicting method steps in accordance with anembodiment.

FIG. 6 is a power plot for a 66 dBm, 3.3 μS incident pulse limited bythe RCLamp4041ZAs configured with minimal spacing in accordance with anembodiment.

FIG. 7 presents power plots, increasing at 1 dB increments, depictingthe power limiting threshold of two RCLamp4041ZAs configured withminimal spacing in accordance with an embodiment.

FIG. 8 is a Vector Network Analyzer (VNA) plot showing return loss fortwo RCLamp4041ZAs configured with minimal spacing in accordance with anembodiment.

FIG. 9 is a VNA plot showing insertion loss for two RCLamp4041ZAsconfigured with minimal spacing in accordance with an embodiment.

FIG. 10 is a VNA Smith Chart showing input match for two RCLamp4041ZAsconfigured with minimal spacing in accordance with an embodiment.

FIG. 11 is graph providing a comparison of rejection performance inaccordance with an embodiment.

FIG. 12 is a VNA plot showing insertion loss for two diodes in parallelwith λ/4 spacing in accordance with an embodiment.

FIG. 13 is a VNA Smith Chart showing input match for dual-diodes withminimal spacing in accordance with an embodiment.

FIG. 14 is a VNA Smith Chart showing input match for dual-diodes withλ/4 spacing in accordance with an embodiment.

FIG. 15 is a graph of compression curves providing a comparison ofrejection performance in accordance with an embodiment.

These and other features of the present embodiments will be understoodbetter by reading the following detailed description, taken togetherwith the figures herein described. The accompanying drawings are notintended to be drawn to scale. For purposes of clarity, not everycomponent may be labeled in every drawing.

DETAILED DESCRIPTION

The features and advantages described herein are not all-inclusive and,in particular, many additional features and advantages will be apparentto one of ordinary skill in the art in view of the drawings,specification, and claims. Moreover, it should be noted that thelanguage used in the specification has been selected principally forreadability and instructional purposes, and not to limit in any way thescope of the inventive subject matter. The invention is capable of manyembodiments. What follows is illustrative, but not exhaustive, of thescope of the invention.

Pulsed high power RF signals differ from ElectroStatic Discharge (ESD).An ESD event is typically a very fast transient discharge from surfaceto surface. The ESD event typically lasts for less than 100 nanoseconds(based on standard ESD waveform definitions) such as in the 300-500picosecond duration. In contrast, the interfering pulsed RF signal canlast for a much longer pulse duration in the microsecond to millisecondrange. The power is also different and as used herein, the pulsed highpower RF signals can be from 27 dBm to sixty-plus dBm.

A TVS diode component provides sufficient power limiting capabilitieswith minimal leakage in a small package size to protect RF receiversfrom interfering high power pulsed RF signals. By comparison, atraditional high power PIN diode, such as the Skyworks CLA4609-086LF hasa large turn on delay, resulting in leakage power passing through beforeprotection initiates, and this leakage power is enough to damagecomponents. In contrast, TVS diodes such as the ESD103-B1-02 and theRClamp4041ZA exhibit no leakage power, sufficient power limitingcapability, and acceptable package sizing to meet protectionrequirements.

The ESD103-B1-02 and RClamp4041ZA are designed to be used as an ESDprotection device. They are not designed to be used to protect againstlong pulse durations. However, we can use them as an example that servesto baseline the TVS performance for power limiting in an RF application.

The use of TVS diodes as protection from high powered pulsed RF signalsis not a typical application as they are designed for the much morecommon transient risk, rather than a repeated, high power, risk as foundin a severe jamming combat environment. Placement of a pair of TVSdevices either adjacent to each other, or at λ/4 (receiver wavelength)separation provides surprisingly good protection. In one example, thesize of the component is a 0201 package size, which is very small incomparison to other solutions. The 0201 Surface Mounted Component (SMC)package measures 0.6 mm by 0.3 mm (0.024″ by 0.012″). The clampinglevels are used for the required protection range and the TVS diodesystem detailed herein is fast enough that no leakage power gets throughfrom turn on delay.

Other applications use a TVS diode as a protection device for typicalESD and lightning strike events meeting IEC6100-4-2ESD (InternationalElectrotechnical Commission immunity standard), different from theprotection provided here. Further, other applications require multipleassociated components rather than the two TVS diodes of theseembodiments. They utilize various supporting components as well asvoltage rails to be functional. An example other configurations employstwo Schottky diodes that allow high power RF signals to pass through,undistorted, to their RF circuit. This is different from describedembodiments using TVS diodes to limit/reflect high power RF pulses,instead of allowing them to pass through.

Using a TVS diode with a smaller package size lowers the intrinsiccapacitance so that it is usable in the RF frequency range. While thedissipative power handling capability is low due to package sizeconstraints, the reflective power handling capability of the TVS dioderemoves a large portion (or all) turn on delays, resulting in no leakagepower. The TVS diode also provides a better short to ground to maximizereflected power and it does not necessarily need to be capable of highpower dissipation since most of the power is reflected. In thisapplication, the TVS diode can be used for longer pulse durations, whileaddressing the leakage power concerns that have previously been anissue. Embodiments solve the leakage concern through fasterresponse/turn on delay times, and smaller package size.

One embodiment for RF applications includes Identification Friend or Foe(IFF) receiver front end protection against pulsed, high power, signals.Certain RF interference details are illustrated in MIL-STD-464A (tables1A, 1B, and 1F) MIL-STD-464C (tables 1, 2, and 6). For example, around 1GHz the maximum acceptable external ElectroMagnetic Environment (EME)ranges from 300 V/m to 2,000 V/m for fixed-wing aircraft.

FIG. 1 illustrates an application environment 100. The environmentdepicts a severe combat jamming scenario. For example, repeatedhigh-power pulses interfere with Identification Friend or Foe (IFF)communications between platforms. Specifically, pulse-modulatedhigh-power RF signal 105 is radiated from a single source, interceptingmultiple targets 110-140. Example targets comprise a fighter jet with anIdentification Friend or Foe (IFF) system 110; an AWACS' surveillancesystem 115; vehicle communications systems 120; ground communications125; naval communication systems 130; aircraft communication systems135; and drone communication and control systems 140. As mentioned, thetargets may be communicating information between each other (such asIFF) that is important to be received properly. Pulsed RF signals couldalso be natural occurrences such as solar flares, in addition tointentional RF signals such as jamming and spoofing. The present systemis designed to prevent overload of the RF receiver and RF front endsystem that is receiving and processing RF signals between targets.

FIG. 2 illustrates a pulse-modulated high-power RF signal waveform 200.The RF pulse 200 is defined by its pulse width 205, peak 210, and pulserepetition rate 215. Terminology includes: Peak is the maximum RF fieldpower; Pulse Width is the length of time an RF pulse is “ON”; PulseRepetition Frequency (PRF) is the number of pulses per second (both ONand OFF time); Pulse Repetition Rate (PRR) is the time period betweenthe pulses which is the inverse of the frequency (PRR=1/PRF); ModulationDepth is the amplitude of the pulse modulation signal; and Duty Cycle isthe ratio of the “ON” to “OFF” time of a pulse-modulated signal. Highpower pulse field levels can be defined by the DO-160 standard andRadiated Susceptibility (RS) test standards. Here, the pulse-modulatedhigh-power RF signal waveform 200 may be, for example, a 1 GHz, 3.3pulse with a power of 28 dBm or more with a repetition rate (PRF) of 500(250 Hz).

The RF pulse 200 is distinguished from an ESD pulse, and the presentsystem involves the RF environment and not electrostatic discharges. Forexample, the ESD pulse typically has a pulse width that is measured inthe picosecond range (0.05 μS to 0.5 μS), and is tested in nanoseconds.The ESD pulse is also typically a higher power level and can be 0.5 kVto 100 kV. Furthermore, the ESD tends to be a one time or non-cyclicalevent. In contrast, each RF pulse is a much longer duration and thepulse width lasts greater than 100 milliseconds. Finally, the RF pulse200 is generally a cyclical or repeating signal with a pulse repetitionrate 215 such as 250 Hz.

FIG. 3 is a device block diagram configuration 300. Components compriseantenna 305; I/O 310; receiver 315; and TVS diode component 320. Theantenna 305 receives the RF signals that are then processed in an I/Oconnection 310 that in one example is a mating connector and a cablefrom the antenna. A TVS diode assembly 315 is coupled to the signalcoming from the antenna 305 and designed to suppress large power signalsthat might damage the receiver 320 but would otherwise allow for thesignals of interest to pass to the receiver 320. The receiver 320 mayhave an RF front end such as amplifiers, filters, analog-to-digitalconverters (ADC) to provide for a digital signal that is then digitallyprocessed by a processor such as an ASIC or FPGA. TVS diode assembly 315is connected in line with the interconnecting conductors/coaxial cableof I/O 305 and before receiver 320.

FIG. 4 is a device detail 400. Components comprise antenna 405; I/Oconnection 410; and receiver 415. I/O connection 410 and receiver 415are electrically connected by shielded coaxial cable 425. Pulsed highpower protection is provided by first TVS diode 430 and second TVS diode435 formed as a dual-diode device in which one end of the first andsecond TVS diodes are in electrical contact with the shielded centerconductor of the cable 425, and the other end of the first and secondTVS diode is coupled to ground. The ground connection can be the shieldof the cable if the TVS diodes are inserted along the cable. In oneexample, the TVS diodes are coupled proximate to the I/O connection.This protection ensures the receiver does not get swamped by large RFpulses. In one example the first bidirectional TVS diode 430 and secondbidirectional TVS diode 435 are separated by distance 440. Inembodiments separation distance 440 is minimal or λ/4 based on theexpected wavelength of the RF signal. As an example, for an RF frequency(f), wavelength (λ), λ=c/f where c is the speed of light (299,792,458m/s). For illustrative purposes, if the RF frequency was 1 GHz, thewavelength would be 30 cm. This would result in a distance of 7.5 cm.

For embodiments, the TVS diode is located on the IO PCB board. However,other embodiments may use the same substrate as the center conductor. Inone embodiment, the TVS diode is a Semtech RClamp4041ZA surface mountdevice with specifications that comprise: size: 0.60×0.30×mm; workingvoltage 4.0 v; capacitance 0.65 pF; and dynamic resistance Ohms.Embodiments are integrated on a printed circuit board of the receiver.

FIG. 5 is a flow chart depicting the RF pulse protection technique 500.The system has a front end protection TVS diode component for an RFreceiver to protect against pulsed high power signals 505. The RFsignal, which may include an RF pulse, is received at the antenna andI/O connection 510. The RF signal at the I/O connection is then receivedat a TVS diode component 515. As noted, in one example the TVS diode iscoupled to the center conductor of the cable. The TVS diodes operate toreflect the pulsed high power signal by the TVS diode component 520,protecting RF receiver 525. During the time the TVS is active andreflecting, the high power RF signal, the receiver will typically notprovide a good RF match. In such embodiments this may degrade theability to receive desired signals. For certain embodiments this isstrictly a protection feature.

According to example, the TVS diode assembly is designed for theparticular application. Table 1 presents system requirements accordingto one example. For an IFF jamming application, the high power RF pulseis expected to be about 60 dBm at 1 GHz.

  P_(in)_max := 60 dBm P_(in)_max := dBm_to_Watts(P_(in)_max) = 1000 WV_(in max) : = {square root over (P_(in)_max_watts ·Impedance_(system))} = 223.607 VRMS V_(in)_max_peak := V_(in)_max ·{square root over (2)} = 316.228 V$I_{in\_ max}:={\frac{V_{{in\_ max}{\_ peak}}}{{Impedance}_{system}} = {6.325A}}$

Based on requirements, this calculation determines the maximum currentthe TVS diode can possibly see, to confirm the TVS is capable ofhandling the current.

Table 2 presents a first embodiment analysis, based on TVSspecifications.

V_(clamp) _(—) _(typ) := 5.6 V V_(clamp) _(—) _(max) := 8 V V_(clamp)_(—) _(typ) _(—) _(dBm) := Voltage_to_dBm(V_(clamp) _(—) _(typ)) =27.974 dBm V_(clamp) _(—) _(max) _(—) _(dBm) := Voltage_to_dBm(V_(clamp)_(—) _(max)) = 31.072 dBm V_(stand) _(—) _(off) _(—) _(dBm) :=Voltage_to_dBm(4 V) = 25.051 dBm P_(dissipation) _(—) _(stead) _(—)_(state) _(—) _(typ) := I_(in) _(—) _(max) · V_(clamp) _(—) _(typ) =35.418 W P_(dissipation) _(—) _(stead) _(—) _(state) _(—) _(max) :=I_(in) _(—) _(max) · V_(clamp) _(—) _(max) = 50.596 W

Based on the characteristics of the TVS, this calculation estimates whenthe typical power limiting should occur where the typical clampingvoltage is 5.6 volts and the maximum clamping voltage is 8 volts.

FIG. 6 is a power limiting plot 600 of two RCLamp4041ZA diodes inparallel with minimal spacing for a 3.3 μs pulse @ 250 Hz with an inputpower of 66 dBm. The horizontal time scale is 500 ns per division, thevertical scale is 10 dBm per division. The plot shows that an inputpower of 66.1 dBm 605 is limited to 29.1 dBm 610, or a reduction of 37dB. Pulses were 1030 MHz 60 and 66 dBm with a PRF OF 500 Hz, held for 10minutes. These results show protection for inputs exceeding the 60 dBmof Table 1 system requirements.

FIG. 7 is a power limiting plot 700 of two RCLamp4041ZA diodes inparallel with λ/4 spacing for a 3.3 μs pulse @ 250 Hz with an inputpower of 66 dBm. The horizontal time scale is 500 ns per division, thevertical scale is 10 dBm per division. The plot shows that an inputpower of 66.1 dBm 705 is limited to 23.3 dBm 710, or a reduction ofabout 43 dB. These results show protection for inputs exceeding the 60dBm of Table 1 system requirements, and better than the minimal spacingperformance of FIG. 6 .

FIG. 8 is a power plot 800 showing the power limiting threshold of twoRCLamp4041ZA diodes in parallel with minimal spacing at 1 dB increments.The horizontal time scale is 500 ns per division, the vertical scale is5 dB per division. Input powers are 25.7 dBm 805, 26.7 dBm 810, and 27.5dBm 815. As seen, an input power of 25.7 dBm 805 does not cause areduction/limitation of the input power. Input power of 26.7 dBm 810,reveals a very small effect at this threshold. Input power of 27.5 dBm815 shows a limiting of the power by about 0.57 dB from about 27.5 dBmto about 27 dBm. Therefore, in this embodiment, two RCLamp4041ZA diodesin parallel with minimal spacing have a power limiting threshold ofabout 26.7 dBm.

FIG. 9 is a Vector Network Analyzer (VNA) plot 900 showing insertionloss for two RCLamp4041ZA diodes in parallel with minimal spacing. Theplot is over an 800 MHz to 1.2 GHz frequency range with a verticalinsertion loss scale of 0.250 dB per division, from −1.250 to +1.250 dB.Insertion loss values range from about −0.25 dB at 800 MHz to about−0.46 at 1.2 GHz. Specific values are −0.2878 dB at 905.26316 MHz 905and −0.4546 dB at 1.2000000 MHz 910. This depicts that thecharacteristics of the TVS diode have little to no effect on the RFtransmission line characteristic impedance.

FIG. 10 is a Vector Network Analyzer (VNA) plot 1000 showing return lossfor two RCLamp4041ZA diodes in parallel with λ/4 spacing. The plot isover an 800 MHz to 1.2 GHz frequency range with a vertical return lossscale of 10 dB per division, from −50 to +50 dB. Return loss valuesrange from about −26 dB at 800 MHz to about −22 at 1.2 GHz. Specificperformance values are −23.082 dB at 978.00000 MHz 1005, −23.262 dB at1.0300000 MHz 1010, and −22.199 dB at 1.0900000 GHz 1015. This depictsperformance that will not hamper receiver reception.

FIG. 11 is a VNA plot 1100 showing return loss for two RCLamp4041ZAdiodes in parallel with minimal spacing. The plot is over an 800 MHz to1.2 GHz frequency range with a vertical return loss scale of dB perdivision, from −50 to +50 dB. Return loss values range from about −20 dBat 800 MHz to about −15 dB at 1.2 GHz. Specific performance values are−18.650 dB at 905.26316 MHz 1105, and −15.816 dB at 1.20000000 GHz 1110.This depicts performance that will not hamper receiver reception.

FIG. 12 is a VNA plot 1200 showing insertion loss for two RCLamp4041ZAdiodes in parallel with λ/4 spacing. The plot is over an 800 MHz to 1.2GHz frequency range with a vertical insertion loss scale of 0.1 dB perdivision, from −0.50 to +0.50 dB. Insertion loss values range from about−0.20 dB at 800 MHz to about −0.30 at 1.2 GHz. Specific performancevalues are −0.2489 dB at 978.00000 MHz 1205, −0.2567 dB at 1.0300000 GHz1210, and −0.2709 dB at 1.0900000 GHz 1215. This depicts performancethat will not hamper receiver reception.

FIG. 13 is a VNA Smith Chart 1300 showing input match for dual-diodeswith minimal spacing for an RCLamp4041ZA. Values at 905.26316 MHz are40.832 Ω, −5.3769Ω, and 32.698 pF 1305; values at 1.200000 GHz are36.318 Ω, −2.8708Ω, and 46.199 pF 1310, showing a good match to the ohmsof the antenna receiver circuit; note the capacitive component ofimpedance.

FIG. 14 is a VNA Smith Chart 1400 showing input match for dual-diodeswith λ/4 spacing for an RCLamp4041ZA. Values at 978.00000 MHz are 45.516Ω, 4.9814Ω, and 810.64 pH 1405; values at 1.0300000 GHz are 46.312 Ω,5.5132Ω, and 851.89 pH 1410, and values at 1.0900000 GHz are 46.776 Ω,6.8168Ω, and 995.34 pH 1415. Note the better input match when comparedwith minimal-spacing configuration. Impedance is close to 50Ω, with aslight inductive component.

FIG. 15 is a graph 1500 of compression curves providing a comparison ofrejection performance. Power output Pout is compared to power input Pinin dBm. Three configurations are shown: single diode 1505; dual diodewith close (adjacent) spacing 1110, and dual diode with λ/4 spacing1515. In this example, the frequency is 1 GHz, therefore the wavelengthis about 30 cm, and λ/4 is about 7.5 cm. While optimum rejection isobtained with λ/4 spacing 1515, close spacing 1510 performs surprisinglybetter than a single diode 1505. A single diode 1505 provides about 27dB of rejection over the span of 60 dBm to 66 dBm input, while dualdiodes with close spacing 1510 provides about 35 dB of rejection, anddual diode with λ/4 spacing 1515 provides about 35 to 43 dB of rejectionover this range.

The foregoing description of the embodiments has been presented for thepurposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed. Manymodifications and variations are possible in light of this disclosure.It is intended that the scope of the present disclosure be limited notby this detailed description, but rather by the claims appended hereto.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the scope of the disclosure. Although operations are depicted inthe drawings in a particular order, this should not be understood asrequiring that such operations be performed in the particular ordershown or in sequential order, or that all illustrated operations beperformed, to achieve desirable results.

Each and every page of this submission, and all contents thereon,however characterized, identified, or numbered, is considered asubstantive part of this application for all purposes, irrespective ofform or placement within the application. This specification is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Many modifications and variations are possible in light ofthis disclosure. Other and various embodiments will be readily apparentto those skilled in the art, from this description, figures, and theclaims that follow. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto.

What is claimed is:
 1. A device for front end protection for an RFreceiver against transient and pulsed high power RF signals comprising:a dual-diode device comprising: a first Transient Voltage Suppressor(TVS) diode; and a second TVS diode in parallel to the first TVS diode;wherein said first TVS diode and said second TVS diode are locatedbetween an RF input/output (I/O) and said RF receiver front end; andwherein the transient and pulsed high power RF signals are suppressed bythe dual-diode device; whereby said RF receiver front end is protectedfrom damage by the transient and pulsed high power RF signals.
 2. Thedevice of claim 1, wherein said first TVS diode and said second TVSdiode are spaced apart by a TVS diode separation distance.
 3. The deviceof claim 1, wherein said first TVS diode and said second TVS diode arespaced apart by a TVS diode separation distance of λ/4 between an RFinput/output and said RF receiver front end.
 4. The device of claim 1,wherein each of said first TVS diode and said second TVS diode has oneend coupled to a center conductor and a second end coupled to ground. 5.The device of claim 1, wherein said dual-diode device is in line withelectrical connections between said RF input/output and said RF receiverfront end.
 6. The device of claim 1, wherein said suppression is areflection of said transient and pulsed high power RF signals, with noleakage.
 7. The device of claim 1, wherein each of said first TVS diodeand said second TVS diode has one end coupled to a center conductor anda second end coupled to a shield of a coaxial cable between said RFinput/output and said RF receiver front end.
 8. The device of claim 2,wherein an insertion loss of said dual diode device is −0.35 dB at 1GHz.
 9. The device of claim 3, wherein an insertion loss of said dualdiode device is −0.25 dB at 1 GHz.
 10. The device of claim 1, whereinsaid dual diode device is located on an Input Output (TO) PCB board. 11.The device of claim 2, wherein a return loss of said dual diode deviceis −18 dB at 1 GHz.
 12. The device of claim 1, wherein a return loss ofsaid dual diode device of claim 3 is −24 dB at 1 GHz.
 13. The device ofclaim 1, wherein each of said first TVS diode and said second TVS diodeis a Semtech RClamp4041ZA TVS diode.
 14. The device of claim 1, whereinsaid RF receiver is an Identification Friend or Foe (IFF) receiver. 15.A method for front end protection for an RF receiver against interferingpulsed high power signals using a Transient Voltage Suppressor (TVS)diode component comprising: providing said front end protection TVSdiode component, wherein said TVS diode component comprises two TVSdiodes; receiving an RF signal at an I/O stage; receiving said RFsignal, output from said I/O stage, at said TVS diode component; anddiverting said pulsed high power signal by said TVS diode component. 16.The method of claim 15, wherein said two TVS diodes are separated by adiode separation distance equal to λ/4.
 17. The method of claim 15,wherein said diverting is a reflection of said interfering pulsed highpower signals.
 18. The method of claim 15, wherein said TVS diodecomponent is provided in line with electrical connections between saidI/O stage and said RF receiver.
 19. The method of claim 16, wherein saidTVS diode component limits said interfering pulsed high power signal by43 dB at 1 GHz.
 20. A system for front end protection for an RF receiveragainst a pulsed high power RF signal comprising: a dual-diode devicecomprising: a first Transient Voltage Suppressor (TVS) diode; and asecond TVS diode electrically parallel to the first TVS device; whereinsaid first TVS diode and said second TVS diode are spaced at λ/4 betweeneach other, and said dual-diode device is electrically connected betweenan RF input/output an Identification Friend to or Foe (IFF) RF receiver;and whereby said RF receiver is protected from damage by said pulsedhigh power RF signal.